How to upgrade a ZTE Open C (French/Europe/US versions)

Update: most of the following instructions are outdated. Please read this:

Step 1 (rooting) is necessary only once. Step 2 (upgrading) can be done everytime you want to upgrade Firefox OS. If you want to save your data, use this tool: Sadly, this only works if your device is already rooted (so it can be done only after step 1).

I use Windows for part 1 (required), and Linux or Mac for part 2. I never tried part 2 with Windows.

Before anything: Install ADB and fastboot on your computer.

1. Root the phone (Windows required)

Where did you buy your phone:

With Open_C_upgrade_Tool, flash the ROM. Common issue if it fails:

Normally, now your phone is unlocked. To check, type: "adb shell id". If it says "root", good. If it says "shell", it didn't work. If "adb" doesn't work on Linux, you need to add a udev rule (google: "udev adb").

2. flash the version of Gecko and Gaia you want

The Open C is compatible with Mozilla's reference phone: The Flame. So you just need to download and flash Flame's builds: (no need to build B2G or Gaia yourself).

At the moment, I recommend Firefox OS 2.1:

Download (gecko) and (gaia).

Download the flash script:

On Mac and Cygwin: ./ -g -G

On Linux: ./

Then, if your fonts look funky, use this: